1. Field of the Invention
The present invention relates to an inner ring press-inserting jig for a pipe joint made of resin, and particularly to an inner ring press-insertion jig for a pipe joint made of resin which is used in the connection of piping for a liquid having high purity of ultrapure water to be handled in a production process of various technical fields such as the production of semiconductor devices, the production of medical equipment and medicines, food processing, and chemical industry. The jig is used for pressingly inserting and fixing into one end portion of a resin pipe member serving as one connecting member of the pipe joint made of resin, a sleeve-like inner ring for enhancing the sealing and locking forces to be exerted between the pipe member and the joint body.
2. Description of the Prior Art
Conventionally, as pipe joints made of resin of this kind, those having a configuration shown in FIG. 14 are known. The pipe joint made of resin shown in FIG. 14 comprises a cylindrical joint body 1 produced from resin having excellent. chemical resistance and heat resistance, such as PFA, PTFE, and ETFE, a sleeve-like inner ring 8, and a cap nut-like pressing ring 9.
In the joint body 1, a cylindrical pipe receiving port 2 is formed in one end in the axial direction, and an inclined sealing face 4 which elongates in a direction intersecting the axis C and forms a tertiary sealing portion 5C that will be described later is formed in the inlet of the pipe receiving port 2. An annular sealing end face 6 which forms a primary sealing portion 5A that will be described later is formed in an inner portion of the pipe receiving port 2. A cylindrical groove 7 which forms a secondary sealing portion 5B that will be described later is formed in a position which is located at a radius which is greater than the annular sealing end face 6 in a radial direction. An external thread portion 3 is formed on the outer periphery of the pipe receiving port 2.
The sleeve-like inner ring 8 is formed so as to have an inner diameter which is equal to the inner diameters of a resin pipe member 10 and a cylinder portion IA of the joint body 1, so as not to impede movement (flow) of a fluid. The inner ring has a fitting portion 11 which can be fitted into the pipe receiving poll: 2 of the joint body 1. A bulge portion 13 which has a mountain-like section shape is formed on the outer side on the tip end side of a pipe member press insertion portion 12 which is formed continuously with the fitting portion 11. An insertion portion 15 of the pipe member 10 is formed which is to be inserted into the pipe receiving port 2 of the joint body 1, and which has an outer peripheral sealing face 14. When the press insertion portion 12 of the inner ring 8 is pressingly inserted into one end portion of the pipe member 10 under a state where the fitting portion 11 projects from the end portion of the pipe member 10, the diameter of the peripheral wall of the pipe member 10 in a place corresponding to the bulge portion 13 is increased to cause the outer peripheral sealing face 14 to abut against the inclined sealing face 4 in the axial direction which is formed in the inlet of the pipe receiving port 2 of the joint body 1, thereby forming the tertiary sealing portion 5C.
In the fitting portion 11 of the inner ring 8 which projects from the pipe member 10, a protruding inner end face 16 is formed. When the insertion portion 15 of the pipe member 10 is inserted into the pipe receiving port 2 of the joint body 1, the protruding inner end face 16 abuts against the annular sealing end face 6 in the axial direction to form the primary sealing portion 5A. Each of the protruding inner end face 16 and the annular sealing end face 6 is formed into a tapered face in which the diameter is gradually reduced toward the inner periphery side. A cylindrical sealing portion 17 which projects in the axial direction outwardly more than the protruding inner end face 16 configured by the tapered. face is integrally projected from a position of the protruding inner end face 16 on the outer side in a radial direction. The cylindrical sealing portion 17 is to be pressingly inserted into the cylindrical groove 7 to form the secondary sealing portion 5B.
In the cap nut-like pressing ring 9, an internal thread portion 18 which is to be screwed to the external thread portion 3 of the joint body 1 is formed in the inner peripheral face of a cylindrical portion 9A, and an annular pressing portion 9B is continuously integrated with an outer end portion of the cylindrical portion 9A. The annular pressing portion 9B elongates toward the axial center and externally presses the pipe member 10. A pressing edge 9C is formed in an inner edge position of the annular pressing portion 9B.
In the pipe joint made of resin having the thus configured components 1, 8, and 9, the press insertion portion 12 of the inner ring 8 is pressingly inserted and fixed into the one end portion of the pipe member 10 to increase the diameter of the peripheral wall of the pipe member 10 in a place corresponding to the bulge portion 13 formed in the press insertion portion 12, whereby both the components 8 and 10 are integrally coupled together to form the insertion portion 15 of the pipe member 10. Under this state, the insertion portion 15 of the pipe member 10 is inserted into the pipe receiving port 2 of the joint body 1 to advance the cylindrical sealing portion 17 of the inner ring 8 into the cylindrical groove 7 of the joint body 1.
Thereafter, the internal thread portion 18 of the pressing ring 9 which is loosely fitted onto and held on the outer side of the pipe member 10 is screwed to the external thread portion 3 of the joint body 1 to cause the pressing ring 9 to screwingly advance toward the joint body 1. Therefore, the inner ring 8 is pressed in the axial direction by the pressing edge 9C of the annular pressing portion 9B, so that the cylindrical sealing portion 17 of the inner ring 8 is pressingly inserted into the cylindrical groove 7 of the joint body 1. As a result, a contact pressure is generated between the inner and outer peripheral faces of the two components 17 and 7, thereby forming the secondary sealing portion 5B which elongates in the axial direction. The pressing ring 9 is further screwingly advanced to be strongly tightened. As a result, the axial length of the secondary sealing portion 5B is increased, and the protruding inner end face 16 of the inner ring 8 abuts against the annular sealing end face 6 of the pipe receiving port 2 of the joint body 1 to generate a contact pressure in the axial direction between the components 16 and 6, thereby forming the primary sealing portion 5A. Furthermore, the outer peripheral sealing face 14 which is formed on the insertion portion 15 of the pipe member 10 abuts in the axial direction against the inclined sealing face 4 which is formed in the inlet of the pipe receiving port 2 of the joint body 1, thereby forming the tertiary sealing portion 5C. As a result, the pipe member 10 is connected to the joint body 1 under a slipping off preventing state and a sealed state.
As a jig for pressingly inserting and fixing the sleeve-like inner ring 8 into the one end portion of the pipe member made of resin 10 in the thus configured pipe joint made of resin, known is an inner ring inserting apparatus which is disclosed in, for example, Japanese Utility Model Publication Laying-Open No. 62-134629. In the inner ring inserting apparatus of the prior art, as shown in FIG. 15, a clamp portion 21 which fixedly holds the pipe member 10 is disposed in one end side of a base arm 20. A grip portion 22, and a toggle lever 23 which is swingably pivotally attached to the grip portion 22 are disposed in the other end side of the base arm 20. A slide shaft 25 is engaged at one end with an end portion of the toggle lever 23, and slidably held by a guide base 24 attached to the base arm 20 while being movingly urged by a spring 28 in a direction along which the shaft is separated from the clamp portion 21. A feed member 27 having a feed arrow 26 which can fittingly hold the inner ring 8 is screwingly fixed to the other end of the slide shaft 25.
In the thus configured inner ring inserting apparatus, the pipe member 10 is clamped by the clamp portion 21, the inner ring 8 is fittingly held by the feed arrow 26 of the feed member 27, and the grip portion 22 is then gripped to strongly pull the toggle lever 23 in the direction of the arrow x in FIG. 15 against the elastic urging force of the spring 28, whereby, as shown in FIG. 16, the feed arrow 26 and the inner ring 8 are inserted and fixed into one end portion of the pipe member 10. After the insertion and fixation are completed, the toggle lever 23 is returned by the urging force of the spring 28, so that the feed arrow 26 is pulled out from the one end portion of the pipe member 10 while leaving the inner ring 8 in the pipe member 10. As a result, the inner ring 8 is inserted and fixed into the one end portion of the pipe member 10, and the diameter of the peripheral wall of the pipe member 10 in a place corresponding to the bulge portion 13 formed by the press insertion portion 12 of the inner ring 8 is increased, thereby forming the insertion portion 15 of the pipe member 10 in which the two components 8 and 10 are integrally coupled together.
However, the inner ring inserting apparatus of the prior art configured as described above has the following problems. Even when a small dimensional error such as that the inner diameter of the pipe member 10 is slightly larger than the outer diameter of the feed arrow 26 of the feed member 27, not only the feed arrow 26 but also the inner ring 8 which is fittingly held thereby cannot be pressingly inserted into the pipe member 10. When the inner ring 8 is forcedly inserted into the pipe member 10, the tip end of the inner ring 8 and the inner peripheral face of the pipe member 10 are damaged.
In order to prevent such problems from arising, the outer diameter of the feed arrow 26 may be set to be smaller than the inner diameter of the pipe member 10. In this case, the inner diameter of the inner ring 8 which is to be fittingly held by the feed arrow is naturally smaller than the inner diameter of the pipe member 10. In an insertion state, therefore, a step is formed between the inner peripheral face of the pipe member 10 and that of the inner ring 8. There arises another problem in that this step tends to cause a liquid to stagnate therein. This is not preferable in a pipe joint which is used for transporting a liquid having high purity or ultrapure water.
It may be contemplated that an end portion of the pipe member made of resin 10 is softened by heating before press insertion and the inner ring 8 is then inserted into the end portion of the pipe member 10 by the feed arrow 26. In this case, there are further problems as follows. A heating apparatus such as a heater must be prepared in order to perform the heating operation. The connecting work cannot be performed until the pipe member 10 is cooled after the press insertion, so that completion of the predetermined work of connecting a pipe joint requires a prolonged time period.